Noncollocated Position Control of Tendon-Sheath Actuated Slender Manipulator

Abstract

The tendon-sheath actuated system is applicable to the mechanism where flexibility and long-distance transmission are required, such as surgical hand and rescue robot. Nevertheless, the severe nonlinearity and flexible structure make it hard to control precisely. Moreover, in some applications, where sensors are difficult to install, precise control is even more arduous. In this brief, a noncollocated position control of a tendon-sheath actuated manipulator is studied. First, the tendon-sheath actuated elastic manipulator of a slender rescue robot is introduced. A linear relationship was measured between the driven displacement and desired displacement of the elastic manipulator. Then, the drive system of the manipulator is modeled as a single-tendon-sheath system, and the transmission model is presented. The sheath configuration of the manipulator actuation system can be identified online, using the method called 3-D reconstruction. To control the tip position of the system without collocated feedback, a combined control method which is based on the transmission model and adaptive sliding mode control is put forward. Finally, the improved accuracy in position control is demonstrated by a series of experiments.